A microlens array is a group of generally spherical lenses arranged two-dimensionally having a center to center spacing of less than about 2 mm. Microlens arrays have various uses as described in European Patent Application 0,426,441 A2, including: (1) to intensify luminance by focusing light in areas around picture elements in non-luminant display devices such as liquid crystal display devices; (2) as a light pick-up means such as a laser disc, compact disc, or optical magnetic disc; (3) as a focusing means for coupling a luminant device or a receptive device to an optical fiber; (4) as a focusing means or an image forming means for focusing incident light in a photoelectric converting zone so as to increase the sensitivity of a primary image sensor used in a solid state image device such as a charge couple device (CCD) or facsimile machine; (5) as an image forming means for forming an image on a sensitive medium to be printed on by a liquid crystal printer or an LED printer; and (6) as a filter for treating photo-information.
Microlens arrays can include hundreds, thousands, and even a million or more microlenses. For example, an array of microlenses having dimensions of 12.5 cm by 18.75 cm and consisting of microlenses having a center to center spacing of 0.25 mm would require the creation of 375,000 microlenses. The cost of fabricating so many microlenses according to known methods can be prohibitive. It would take literally hundreds of hours to machine the 375,000 concave cavities required to produce a mold capable of making the microlens array. Furthermore, any mistake made during the machining process might require a restart.
It would be desirable to have a method of making an array of microlenses which was faster and less expensive than currently known methods.